Commit my WIP on constexpr support. This commit: an XFAILed test and treating constexpr as a top-level const.

llvm-svn: 105752

clang/lib/Sema/SemaType.cpp

@@ -860,7 +860,7 @@ QualType Sema::BuildMemberPointerType(QualType T, QualType Class,
     T = Context.getCanonicalType(T);
   }
 
-  // C++ 8.3.3p3: A pointer to member shall not pointer to ... a member
+  // C++ 8.3.3p3: A pointer to member shall not point to ... a member
   //   with reference type, or "cv void."
   if (T->isReferenceType()) {
     Diag(Loc, diag::err_illegal_decl_mempointer_to_reference)
@@ -1335,6 +1335,11 @@ TypeSourceInfo *Sema::GetTypeForDeclarator(Declarator &D, Scope *S,
     }
   }
 
+  // If there's a constexpr specifier, treat it as a top-level const.
+  if (D.getDeclSpec().isConstexprSpecified()) {
+    T.addConst();
+  }
+
   // Process any function attributes we might have delayed from the
   // declaration-specifiers.
   ProcessDelayedFnAttrs(*this, T, FnAttrsFromDeclSpec);

clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p1.cpp

@@ -0,0 +1,78 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// XFAIL: *
+
+struct notlit {
+  notlit() {}
+};
+struct notlit2 {
+  notlit2() {}
+};
+
+// valid declarations
+constexpr int i1 = 0;
+constexpr int f1() { return 0; }
+struct s1 {
+  constexpr static int mi = 0;
+};
+
+// invalid declarations
+// not a definition of an object
+constexpr extern int i2; // x
+// not a literal type
+constexpr notlit nl1; // x
+// function parameters
+void f2(constexpr int i) {} // x
+// non-static member
+struct s2 {
+  constexpr int mi; // x
+};
+// redeclaration mismatch
+constexpr int f3(); // n
+int f3(); // x
+int f4(); // n
+constexpr int f4(); // x
+
+// template stuff
+template <typename T>
+constexpr T ft(T t) { return t; }
+
+// specialization can differ in constepxr
+template <>
+notlit ft(notlit nl) { return nl; }
+
+constexpr int i3 = ft(1);
+
+void test() {
+  // ignore constexpr when instantiating with non-literal
+  notlit2 nl2;
+  (void)ft(nl2);
+}
+
+// Examples from the standard:
+constexpr int square(int x);
+constexpr int bufsz = 1024;
+
+constexpr struct pixel { // x
+  int x;
+  int y;
+  constexpr pixel(int);
+};
+
+constexpr pixel::pixel(int a)
+  : x(square(a)), y(square(a))
+  { }
+
+constexpr pixel small(2); // x (no definition of square(int) yet, so can't
+                          // constexpr-eval pixel(int))
+
+constexpr int square(int x) {
+  return x * x;
+}
+
+constexpr pixel large(4); // now valid
+
+int next(constexpr int x) { // x
+      return x + 1;
+}
+
+extern constexpr int memsz; // x